1. Field of the Invention
The present invention relates to a baby trailer and more particularly, to a baby trailer frame mounting structure, which consists of a lower number of component parts and uses a control member to match with spring members for locking the front wheel holder, facilitating quick mounting and dismounting of the front wheel holder.
2. Description of the Related Art
FIG. 1 illustrates the frame structure of a conventional baby trailer. The baby trailer 4 comprises a base frame 44, two rear wheels 41 respectively and pivotally mounted on two opposite sidebars 441 of the base frame 44, a trailer bar 42 connected to one sidebar 441 and forwardly protruding over the front bar 442 of the base frame 44, and connectable to a bicycle, a front wheel holder mounting frame assembly 43 located on the front side of the trailer bar 42, a front wheel holder 45 coupled to the front wheel holder mounting frame assembly 43 and pivotally holding a pair of front wheels 451. According to this design, a special hand tool is necessary when connecting the front wheel holder 45 to the front wheel holder mounting frame assembly 43 or dismounting the front wheel holder 45 from the front wheel holder mounting frame assembly 43.
FIGS. 2-5 illustrate another front wheel holder mounting frame assembly for securing a front wheel holder to a baby trailer according to the prior art. According to this design, the front wheel holder mounting frame assembly 3 consists of a first frame block 31, a second frame block 32, a spring holder 33, two spring members 34 and a control member 35. The first frame block 31 and the second frame block 32 are attached together and affixed to one sidebar of the base frame unit of the frame structure of the baby trailer with 6 pcs of fastening members 36. This design of front wheel holder mounting frame assembly has drawbacks as follows:    1. During installation, the spring members 34 are respectively attached to respective support rods 330 of the spring holder 33, and then the coupling hole, referenced by 331, of the spring holder 33 is coupled to a locating block 321 of the second frame block 32, and then hold the spring holder 33 in an inclined position and attach two stop faces 351 of the control member 35 against respective distal ends 341 of the spring members 34 to move a stop plate 352 of the control member 35 over a locating plate 322 of the second frame block 32 and then force the control member 35 downwards into position (see FIG. 4). When forcing the control member 35 against the spring members 34 in a rush during installation, the spring members 34 may be forced to jump away, complicating the installation operation. After installation of the control member 35 with the spring holder 33 and the spring members 34 in the second frame block 32, a positioning hole 320 of the second frame block 32 is coupled to one sidebar of the base frame unit of the baby trailer, and then the first frame block 31 is attached to the same sidebar of the base frame unit of the baby trailer and affixed with the second frame block 32 to the sidebar of the base frame unit of the baby trailer with the fastening members 36. This installation procedure is complicated, wasting much installation labor and time.    2. Fabrication of the first frame block 31, the second frame block 32, the spring holder 33 and the control member 35 is complicated and requires different molds, increasing the manufacturing and inventory cost.    3. The first frame block 31 and the second frame block 32 each have a big size, wasting much packing material and requiring much storage and delivery space.